Constant \Con"stant\, n.

1. (Astron.) A number whose value, when ascertained (as by observation) and substituted in a general mathematical formula expressing an astronomical law, completely determines that law and enables predictions to be made of its effect in particular cases.

2. (Physics) A number expressing some property or condition of a substance or of an instrument of precision; as, the dielectric constant of quartz; the collimation constant of a transit instrument.

Aberration constant, or Constant of aberration (Astron.), a number which by substitution in the general formula for aberration enables a prediction to be made of the effect of aberration on a star anywhere situated. Its value is 20[sec].47.

Constant of integration (Math.), an undetermined constant added to every result of integration.

Gravitation constant (Physics), the acceleration per unit of time produced by the attraction of a unit of mass at unit distance. When this is known the acceleration produced at any distance can be calculated.

Solar constant (Astron.), the quantity of heat received by the earth from the sun in a unit of time. It is, on the C. G. S. system, 0.0417 small calories per square centimeter per second. --Young.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Constant \Con"stant\, a. [L. onstans, -antis, p. pr. of constare to stand firm, to be consistent; con- + stare to stand: cf. F. constant. See Stand and cf. Cost, v. t.]

1. Firm; solid; fixed; immovable; -- opposed to fluid. [Obs.]

If . . . you mix them, you may turn these two fluid liquors into a constant body. --Boyle.

2. Not liable, or given, to change; permanent; regular; continuous; continually recurring; steadfast; faithful; not fickle.

Both loving one fair maid, they yet remained constant friends. --Sir P. Sidney.

I am constant to my purposes. --Shak.

His gifts, his constant ourtship, nothing gained. --Dryden.

Onward the constant current sweeps. --Longfellow.

3. (Math. & Physics) Remaining unchanged or invariable, as a quantity, force, law, etc.

4. Consistent; logical. [Obs.]

--Shak.

Syn: Fixed; steadfast; unchanging; permanent; unalterable; immutable; invariable; perpetual; continual; resolute; firm; unshaken; determined.

Usage: Constant, Continual, Perpetual. These words are sometimes used in an absolute and sometimes in a qualified sense. Constant denotes, in its absolute sense, unchangeably fixed; as, a constant mind or purpose. In its qualified sense, it marks something as a ``standing'' fact or occurence; as, liable to constant interruptions; constantly called for. Continual, in its absolute sense, coincides with continuous. See Continuous. In its qualified sense, it describes a thing as occuring in steady and rapid succession; as, a round of continual calls; continually changing. Perpetual denotes, in its absolute sense, what literally never ceases or comes to an end; as, perpetual motion. In its qualified sense, it is used hyperbolically, and denotes that which rarely ceases; as, perpetual disturbance; perpetual noise; perpetual intermeddling.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Constant \Con"stant\, n.

1. That which is not subject to change; that which is invariable.

2. (Math.) A quantity that does not change its value; -- used in countradistinction to variable.

Absolute constant (Math.), one whose value is absolutely the same under all circumstances, as the number 10, or any numeral.

Arbitrary constant, an undetermined constant in a differential equation having the same value during all changes in the values of the variables.

Source: Webster's Revised Unabridged Dictionary (1913)